* {
    margin: 0;
    padding: 0;
    font-size: 20px;
    color: #333;
  }
  
  ul, ol, li {
    list-style: none;
  }
  
  input, button, textarea, select {
    outline: none;
    font-size: 20px;
  }
  
  a, a:hover, a:link, a:visited, a:active {
    text-decoration: none;
    color: #333;
    font-size: 20px;
  }
  
  img {
    width: 100%;
    height: 100%;
    display: block;
    cursor: pointer;
  }
  
  .container {
    width: 1200px;
    margin: 0 auto;
  }

  /* 新加了一些逻辑 */
  button{
    cursor: pointer;
    outline: none;
  }

  input{
    outline: none;
  }

  .header {
    height: 80px;
    background-color: skyblue;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 40px;
    color: #fff;
    position: relative;
  }

  .header > p {
    position: absolute;
    right: 30px;
    top: 50%;
    margin-top: -15px;
    
  }

  .header > p > span {
    display: none;
  }

  .header > p > span.active {
    display: block;
  }

  .footer {
    width: 100%;
    height: 300px;
    background-color: skyblue;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 100px;
    font-weight: 700;
  }
  